title: The solution structure of a tetraheme cytochrome from Shewanella frigidimarina reveals a novel family structural motif.
abstract: The bacteria belonging to the genus Shewanella are facultative anaerobes that utilize a variety of terminal electron acceptors which includes soluble and insoluble metal oxides. The tetraheme c-type cytochrome isolated during anaerobic growth of Shewanella frigidimarina NCIMB400 ( Sfc) contains 86 residues and is involved in the Fe(III) reduction pathways. Although the functional properties of Sfc redox centers are quite well described, no structures are available for this protein. In this work, we report the solution structure of the reduced form of Sfc. The overall fold is completely different from those of the tetraheme cytochromes c 3 and instead has similarities with the tetraheme cytochrome recently isolated from Shewanella oneidensis ( Soc). Comparison of the tetraheme cytochromes from Shewanella shows a considerable diversity in their primary structure and heme reduction potentials, yet they have highly conserved heme geometry, as is the case for the family of tetraheme cytochromes isolated from Desulfovibrio spp.
authors.affiliation: Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, 2780-156 Oeiras, Portugal.
authors.forename: Vitor B
authors.initials: VB
authors.lastname: Paixão
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Salgueiro
authors.forename: Lorraine
authors.initials: L
authors.lastname: Brennan
authors.forename: Graeme A
authors.initials: GA
authors.lastname: Reid
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Chapman
authors.forename: David L
authors.initials: DL
authors.lastname: Turner
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D003901:Desulfovibrio / Q000201:enzymology; D006418:Heme / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry / Q000378:metabolism; D017510:Protein Folding; D020592:Shewanella / Q000201:enzymology*; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D010087:Oxides; D006418:Heme; D045304:Cytochromes c; D007501:Iron